This invention relates to vehicles in which the driving power from the conventional engine drive may be supplemented by kinetic energy stored in a rotating flywheel drive, i.e., vehicles having a hybrid drive arrangement.
An example of a hybrid drive arrangement is given in German patent application DE-AS No. 29 33 542. In this type of hybrid drive arrangement, the storage flywheel is the same element as the engine flywheel and there is a clutch located between the flywheel (which is normally present in reciprocating piston type engines to equalize non-uniformities of engine output torque and prevent stalling at idling) and the engine crankshaft. However, this dual-purpose flywheel, which is a storage flywheel and an engine flywheel, must have a substantially larger mass moment of inertia than a conventional engine flywheel, which need only have sufficient mass to compensate for the torque irregularities of the crankshaft, if a sufficient amount of kinetic energy to help drive the vehicle is to be available. If a flywheel with a large mass moment of inertia is used, the vehicle will operate sluggishly on acceleration, since the engine must accelerate not only the vehicle, but also the heavy storage flywheel.